kettle

kettle, oval depression found in glacial moraines, which are landforms made up of rock debris. When a glacier melts and draws away from an area, a block of ice may break off and be covered by earth and rock. As the block melts, the ground above it subsides, forming a kettle. Kettles may be deeper than 100 ft (30 m) and more than 1 mi (1.6 km) in diameter. Pitted outwash plains contain many kettles.